The invention relates to a method for determining tool wear, particularly in the cutting of tungsten wires, as well as an arrangement for the implementation of said method.
Tungsten wires are employed, for example, as coils in the manufacture of incandescent lamps. Since tungsten wire coils are usually manufactured in wound form in a continuing sequence on a core, they must be cut into lengths with a specific dimension in accordance with its intended use. In the case of coils that are wound with a break, the separation occurs in the center of the break. Accordingly, the cutting into sections usually ensues with the assistance of a fixed injector knife and a blade knife which is moved back and forth at right angles with respect to the coil. During the cutting of the incandescent lamp coils, as the cutting tools increasingly wear, a more or less strong formation of hooks occurs at the coil. Such hooks lead to the mutual entanglement of the coils and then disrupt the automatic sequence in the lamp manufacture and, moreover, lead to rejects which lie in the magnitude of 2% of the manufacturing quota. Accordingly, a particular problem arises, since the tool wear producing the formation of hooks cannot be predicted as a result of being subject to very great fluctuation. Experience has shown that the actual number of cuts, i.e., the plurality of cuts which can be carried out without re-grinding the tools, lies between 10,000 and 30,000 cuts. This fluctuation in the number of cuts can be attributed, among other things, to differences in the tenacity of the tungsten wire. Thus, the tools must be constantly monitored, which was previously carried out in such a manner that random samples of the cut coils were checked under a magnifying glass for the formation of hooklets every five to ten minutes. This monitoring operation is very personnel-intensive and requires very reliable personnel.